Over the past decades, so-called “smart” devices have transitioned from being mainly a fixed technology (for example “main frame” computers and desktop computers), to being portable (for example laptop computers) and even wearable (for example PDA's and “smart” cellular telephones). Currently, advances are being made in so-called “embedded” wearable technology, whereby “smart” technology need not be located in separately worn devices, but instead can be integrated into clothing and other commonly worn accessories such as watches and eyeglasses.
The miniaturization of electronic devices has been enabled, among other advances, by improved methods for interconnecting electronic components. In particular, circuits which were once wired by hand have been replaced by so-called “printed” circuits, where complex interconnections are provided between surface-mounted devices by conducting paths that are printed onto a rigid, multi-layer substrate, or “circuit board.”
Due to the complexity of typical electronic circuits, interconnecting features that are commonly required in contemporary circuit board designs include:                signal layers;        power layers;        ground layers;        vias;        bonded interconnect pads;        separable connectors; and        thermal management for high power devices.        
The availability of active and conductive fibers is an important step toward integrating electronic systems into fibers that are included in fabrics, whereby active devices are not sitting on a surface mount solder pad, but instead are embedded within the fibers of a garment or other textile article. However, current textile production methods cannot provide the complex interconnections that are required for creating multi-component circuits using such fiber-embedded devices.
It is clear that the preform processes by which active devices are produced will evolve over time, and it is reasonable to expect that such devices will take on a more continuous character. This will provide an enhanced capability to distribute the devices within textile fibers. However, improved approaches are needed for creating a continuous capability for intercommunication between the fiber-embedded devices of a textile-embedded circuit, and for interconnecting the devices between textile panels and with exterior devices and power sources.
Polymeric fibers have become ubiquitous in applications such as textile fabrics, due to their excellent mechanical properties and availability of low-cost, high-volume processing techniques. In particular, many polymer fibers and films can be formed by “drawing” or otherwise elongating relatively macroscopic preforms so as to create much thinner, elongated versions thereof. In some cases, a preform having a plurality of active components assembled in a desired structure can be drawn or otherwise elongated so as to dramatically reduce at least one dimension of the preform, and thereby reduce the structure and configuration of the active components to a micro-scale or nanoscale. Accordingly, drawing of structured, multi-component polymeric preforms can provide a cost-effective method for producing fibers, films, and other polymeric constructs having micro-structurers and/or nanostructures incorporated therein.
An example of this approach is disclosed in U.S. Pat. No. 7,311,962, incorporated herein by reference in its entirety for all purposes. U.S. Pat. No. 7,311,962 discloses the creation of electromagnetic waveguides, fiber optics, and other optically active structures incorporating dielectric mirrors by applying a coating of a chalcogenide glass to a thermoplastic polymer film, creating a preform by rolling the film about a core, for example a poly(ether-sulfone) (“PES”) core, and then drawing the preform at an elevated temperature to create a fiber comprising a core surrounded by a plurality of layers of continuous, alternating, closely spaced glass and polymer layers. By appropriate selection of the dielectric constants of the glass and polymer, and of the layer spacing, the layers can be configured so as to almost perfectly reflect electromagnetic waves at desired wavelengths.
Because it is necessary for active, multi-component fibers to contain materials that are designed to provide electrical, optical, and/or sensor functions, such fibers must of necessity contain materials that are not normally used in fibers. Often, these active component materials do not have properties consistent with bending, abrasion and/or other textile requirements. For example, the fibers disclosed by U.S. Pat. No. 7,311,962 can be configured with a variety of desirable properties, such conduction of light, as well as absorption and/or reflection of incident electromagnetic radiation within selected wavelength bands. However, practical applications of the disclosed fibers are limited, because the glass layers tend to fracture and disintegrate when the fibers are bent.
This inability of active, multi-component fibers to bend freely precludes many applications of interest, such as incorporation into wearable garments for the purpose of inhibiting IR vision detection by blocking infra-red emissions, or of facilitating identification of friendly forces by emitting or reflecting easily identified patterns when irradiated by specifically chosen wavelengths of light. The approach of U.S. Pat. No. 7,311,962 is also limited to continuous active elements, i.e. continuous layers of polymer and glass films, and is not easily extended to applications that would require, for example, a plurality of discrete, spaced-apart, interconnected sensors encapsulated within a fiber.
E-fabrics, also sometimes referred to as e-textiles, smart garments, smart clothing, electronic textiles, smart textiles, and smart fabrics, are fabrics (or garments or other items made from fabrics) that enable the digital components of an electronic system to be attached to the fabric or even embedded within the fabric, such that the interconnections between the components are provided by conductors that are integral with the fabric. Such fabrics and the articles made from them have the ability to do many things that traditional fabrics cannot, including communicate, transform, and conduct energy.
Smart textiles can be aesthetic and/or performance enhancing. For example, various smart fabrics can light up and/or can change color. Performance enhancing smart textiles have applications in athletics, extreme sports, and military applications. These include fabrics designed to regulate body temperature, reduce wind resistance, and control muscle vibration. Other smart fabrics have been developed for protective clothing, to guard against extreme environmental hazards such as radiation and the effects of space travel. The health and beauty industry is also taking advantage of these innovations to provide, for example, drug-releasing medical textiles, and many designs for wearable technology and wearable computing systems depend upon interconnections provided by e-textiles. In addition to wearable applications, e-textiles also have application in other fields such as interior design.
With reference to FIG. 1, conducting inks can be printed 100 onto one or both sides of the fabric using either 2D or 3D printing, or stitched onto the fabric using applique stitching 102. Conductors can also be woven into the fabric itself as fibers in either or both of the warp and fill directions. As the complexity of the fabric circuitry increases, it can becomes necessary to direct conductors in a plurality of paths on or within the fabric that cross over each other, for example by printing conductors on both sides of a fabric, or by weaving insulated wires as fibers in both the warp and fill directions. Furthermore, a fabric with more than two “levels” (i.e. planes) of fibers can be provided by including a plurality of plies in the fabric 104. An e-fabric panel or garment can include interconnections between these integral conductors and/or connection pads that provide connectivity between the integral conductors and external devices.
Of course, it is not sufficient merely to incorporate conductors onto or into a fabric. It is also necessary to provide connection points or “pads” for connecting the conductors with embedded and/or attached devices. And in more sophisticated designs, it can be necessary to provide vias that form bridging connections between conductors that cross over each other in the fabric.
General considerations that typically apply to conductors in e-fabrics include:                conductors must operate across textile seams;        conductors must provide connections on both sides of the fabric;        conductors must connect to devices such as active buttons and multi-component fibers;        conductors included in stretch fabrics must be able to stretch;        textile bias stretch can put conductors into shear;        the potential for copper conductors to become work-hardened must be controlled;        printed conductors have to be wash fast and durable; and        the conductors and the method of manufacture must be low in cost.        
Embodiments that include printed conductors 100 must use conductive inks that are fully wash fast. Some include cover coats and/or binders. If a conductive ink that includes a noble metal filler is used, printers having microelectromechanical systems (“MEMS”) print head configurations cannot be used because of the large sizes of the noble metal particles. These include various digital printers, screen printers, and some specialized digital printers.
Most graphene-based inks are compatible with digital printing using MEMS print heads. However, some binders used in graphene ink designs create thermal challenges (250 C, 480 F).
When printed conductors are applied on cut panels of fabrics, registration to the textile is not required. However, it is typically necessary to include fabric vias so as to provide pads or contacts on opposing sides of the textile. In addition, seam vias are often required, as well as connection pads and/or contact pads.
E-fabrics that include woven conductors require extensive design interaction, from woven patterning to garment patterning. Among the various e-fabric conductor approaches, woven conductors are generally the least visible. However, woven conductors are typically not compatible with knit fabrics.
Typically, woven conductors are incorporated into fabrics as roll goods, thereby requiring that cut panels be registered to woven patterns so as to align the woven conductors to the cut patterns. Also, a second production step is typically required so as to provide vias between warp and fill conductors, including vias provided in the seams.
While the requirements to provide connection pads and vias are somewhat analogous to vias and connection pads in conventional printed circuit boards, they give rise to several problems that do not apply to traditional printed circuit boards, due to the flexibility of the fabric, the necessity of including seams in the fabric, and the necessity of exposing the fabric to conventional washing procedures.
While it is sometimes possible to integrate electronic devices within an e-fabric, many devices are too large to be incorporated into a fabric, and many devices are incompatible or only semi-compatible with washing procedures that are applicable to a fabric. For example, such devices may be compatible with water, but not with the wetting agents and detergents used in washing. They may be compatible with the heat and moisture used in drying, but not with the tumbling actions of a dryer. Accordingly, it is often desirable or necessary to removably attach electronic devices to surfaces of an e-fabric as “external” devices that communicate with each other through the conductors provided by the e-fabric. This approach also has the advantage of making it easier to service and upgrade the attached devices without any need to modify the underlying e-fabric.
Metal snaps are a well-known approach for providing electrical connectivity between conductors of an e-fabric and an external device. While snaps are typically rigid or semi-rigid, they are small in size, so that this approach works well when it is necessary to make only a few connections, typically from 2-4 connections. When more connections are needed, another approach is to use multi-contact connectors instead of simple snaps. Examples are given in U.S. Pat. Nos. 3,991,563, 6,563,424, and 7,462,035, all of which are incorporated herein in their entirety for all purposes.
However, as the required number of connections becomes even larger, rigid snaps and rigid multi-contact connectors become unsatisfactory, because the inclusion of large, rigid connectors and/or a large number of smaller rigid connectors can unduly impair the flexibility of the underlying fabric.
Throughout history, various approaches have been implemented in attempts to generate and control complex musical effects in live music concerts. Examples include a symphony orchestra, in which many instruments capable of producing a variety of different sounds are brought together to be played by a group of separate musicians under the unifying control of a director. However, this approach has the disadvantage of requiring the coordinated action of a large number of people. Perhaps the most successful historical approach for creating complex musical effects that are controlled by a single individual is the concert organ, having many ranks of pipes controlled by a plurality of keyboards and pedal sets.
While the desire to combine and control a large number of varied sounds in a complex manner has been longstanding, both the variety of possible acoustic effects and the range of possibilities for controlling them has increased exponentially in recent times as music has transitioned from traditional analog devices (i.e. acoustic musical instruments) to digitally recorded and/or generated compositions. The computing power and speed of devices that can control digital media has increased dramatically, and continues to do so. As a result, a modern live musical concert may present a complex mixture of various effects, including music generated by live musicians, pre-recorded music, delayed playback of live music, live mashups of pre-recorded musical tracks, and/or music that is generated by software in an entirely digital manner.
Furthermore, live concerts often go beyond sound and also include visual presentations, such as lighting effects and even pyrotechnics. Accordingly, it is more accurate to refer to such live concerts as being audiovisual, where the term is used herein to refer to any live presentation that is flexibly controlled in real time and that includes any combination of audio and/or visual presentation.
Controlling a complex array of audiovisual aspects in real time can be a significant challenge for the presenters of a modern musical performance. While the capabilities of digital media devices and digital control systems has increased dramatically, human beings continue to have only two hands and two feet that can be used for controlling audiovisual systems in real time. Of course, some or all aspects of a performance could be pre-determined and pre-programmed, but doing so would diminish or eliminate the spontaneous creativity and audience interaction that are unique and highly desirable features of live performances.
Accordingly, a live audiovisual presentation often requires a cooperative effort by a staff of technicians to operate and control all of the devices used in the performance, thereby reducing the degree to which a solo or “star” performer maintains creative and spontaneous control over the performance. Also, the cost and logistical demands involved in gathering a staff and acquiring and fielding a complex control system tends to restrict the creation and spontaneous control of complex audiovisual presentations to large scale events, thereby excluding most musicians from enjoying and experimenting with real-time control over the full range of live audiovisual effects that devices and systems of relatively modest costs could otherwise produce. In other words, it is often the lack of any means to control audiovisual systems in real time, and not the cost and availability of the audiovisual devices themselves, that limits access of artists to creative audiovisual effects.
One approach that has been tried is the use of a band that can be attached to a user's arm in direct contact with the skin, whereby the band is able to sense muscle activity of the user's forearm. This bio-sensing approach has the advantage of allowing the user to use parts of the body other than the hands and feet to control aspects of an audiovisual presentation system. However, bio-sensing requires direct and firm skin contact of the sensors, which can be uncomfortable and cumbersome for the user. Also, it can be problematic to combine this approach with conventional hand manipulation of buttons, sliders, and other controls, because most of the muscles that control the hand and fingers are located in the forearm.
What is needed, therefore, are techniques for registering textiles for forming interconnections, cutting vias into fibers with active components, and forming interconnections between textile panels and with exterior devices. Furthermore, for some applications there is also a need to provide these interconnectivity features while at the same time maintaining or enhancing an esthetic appearance of the fabric.
What is also needed is a highly flexible drawn fiber having continuous and/or discrete active elements encapsulated therein. What is also needed are techniques for connecting e-fabric conductors with internal and external devices, and for providing vias that interconnect conductors that cross each other within the fabric.
What is also needed is a flexible system for forming large numbers of electrical interconnections between an external device and the conductors of an e-fabric, while not unduly impairing the flexibility of the underlying fabric.
What is also needed are e-fabrics, including stretchable e-fabrics, having conductors that can be economically applied to fabric panels and garments, including across the seams thereof, without concern for registration between the conductors and the underlying fabric, and without concern for registration between panels of a garment or other multi-panel fabric assembly.
And what is also needed is a control system that enables a single user to control a large number of aspects of a digital audiovisual presentation in real time, without requiring direct skin contact by sensors or direct sensing of the users muscle activity.